Although the study of TM(Thermo Mechanics),HM(Hydraulic-Mechanics) and THM(Thermo-Hydraulic-Mechanics) coupling under a loading test have been under development,rock failure analysis under THM coupling and unloading i...Although the study of TM(Thermo Mechanics),HM(Hydraulic-Mechanics) and THM(Thermo-Hydraulic-Mechanics) coupling under a loading test have been under development,rock failure analysis under THM coupling and unloading is an emerging topic.Based on a high temperature triaxial unloading seep test for phyllite,this paper discusses the deformation and failure mechanism of phyllites under the "H M,T→H,T→M" incomplete coupling model with unloading conditions.The results indicate that the elastic modulus and initial permeability decrease and the Poisson's ratio increases with increasing temperature;the elastic modulus decreases and the Poisson's ratio and initial permeability increase with increasing water pressure.During the unloading process,rock penetrability is small at the initial elastic deformation phase,but the penetrability increases near the end of the elastic deformation phase;mechanisms involving temperature and water pressure affect penetrability differently.Phyllite failure occurs from the initial thermal damage of the rock materials,splitting and softening(which is caused by pore water pressure),and the pressure difference which is formed from the loading axial pressure and unloading confining pressure.The phyllite failure mechanism is a transtensional(tension-shearing) failure.展开更多
目的:通过分析单胎妊娠宫颈机能不全(CI)患者行McDonald宫颈环扎术后不良妊娠结局的相关危险因素,建立风险预测模型。方法:回顾分析2012年1月至2021年12月于广西医科大学第一附属医院产科行McDonald宫颈环扎术并分娩的CI患者的临床资料...目的:通过分析单胎妊娠宫颈机能不全(CI)患者行McDonald宫颈环扎术后不良妊娠结局的相关危险因素,建立风险预测模型。方法:回顾分析2012年1月至2021年12月于广西医科大学第一附属医院产科行McDonald宫颈环扎术并分娩的CI患者的临床资料,利用logistic回归分析筛选不良妊娠结局的预测变量,R软件绘制列线图,ROC曲线、校准图、决策曲线等评估预测效能及临床价值。内部验证采用1000次Bootstrap重抽样。结果:羊膜囊膨出、术前宫颈长度(CL)<25mm、羊水沉积物(AFS)与不良妊娠结局密切相关。据此建立预测公式:Logit(P)=-0.726+1.775×羊膜囊膨出(否:0,是:1)+1.127×术前CL(CL≥25mm:0,CL<25mm:1)+1.672×AFS(无:0,有:1),进而可视化绘制成Nomogram列线图模型。模型的AUC为0.741,Hosmer-Lemeshow good of fit test(H-L检验)P>0.05,Brier得分0.199,校准图中校准曲线与标准曲线相接近。决策曲线表明当模型的阈概率在32%~88%之间时,其具备一定的临床决策价值。经Bootstrap内部验证后模型校正的AUC为0.736,校准曲线显示一致性较好。结论:该预后模型具备一定的临床价值,能在产前筛选出宫颈环扎术后的高危孕妇,协助产科医师为患者拟定个性化的诊疗措施以改善妊娠结局。展开更多
基金supported by National Natural Science Foundation of China (Grant No. 41102189,No. 41002110 and No. 41230635)Projects of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Grant No. SKLGP2009Z002,No. SKLGP2009Z012)Research Fund for the Doctoral Program of Higher Education of China(Grant No. 20105122110008)
文摘Although the study of TM(Thermo Mechanics),HM(Hydraulic-Mechanics) and THM(Thermo-Hydraulic-Mechanics) coupling under a loading test have been under development,rock failure analysis under THM coupling and unloading is an emerging topic.Based on a high temperature triaxial unloading seep test for phyllite,this paper discusses the deformation and failure mechanism of phyllites under the "H M,T→H,T→M" incomplete coupling model with unloading conditions.The results indicate that the elastic modulus and initial permeability decrease and the Poisson's ratio increases with increasing temperature;the elastic modulus decreases and the Poisson's ratio and initial permeability increase with increasing water pressure.During the unloading process,rock penetrability is small at the initial elastic deformation phase,but the penetrability increases near the end of the elastic deformation phase;mechanisms involving temperature and water pressure affect penetrability differently.Phyllite failure occurs from the initial thermal damage of the rock materials,splitting and softening(which is caused by pore water pressure),and the pressure difference which is formed from the loading axial pressure and unloading confining pressure.The phyllite failure mechanism is a transtensional(tension-shearing) failure.
文摘目的:通过分析单胎妊娠宫颈机能不全(CI)患者行McDonald宫颈环扎术后不良妊娠结局的相关危险因素,建立风险预测模型。方法:回顾分析2012年1月至2021年12月于广西医科大学第一附属医院产科行McDonald宫颈环扎术并分娩的CI患者的临床资料,利用logistic回归分析筛选不良妊娠结局的预测变量,R软件绘制列线图,ROC曲线、校准图、决策曲线等评估预测效能及临床价值。内部验证采用1000次Bootstrap重抽样。结果:羊膜囊膨出、术前宫颈长度(CL)<25mm、羊水沉积物(AFS)与不良妊娠结局密切相关。据此建立预测公式:Logit(P)=-0.726+1.775×羊膜囊膨出(否:0,是:1)+1.127×术前CL(CL≥25mm:0,CL<25mm:1)+1.672×AFS(无:0,有:1),进而可视化绘制成Nomogram列线图模型。模型的AUC为0.741,Hosmer-Lemeshow good of fit test(H-L检验)P>0.05,Brier得分0.199,校准图中校准曲线与标准曲线相接近。决策曲线表明当模型的阈概率在32%~88%之间时,其具备一定的临床决策价值。经Bootstrap内部验证后模型校正的AUC为0.736,校准曲线显示一致性较好。结论:该预后模型具备一定的临床价值,能在产前筛选出宫颈环扎术后的高危孕妇,协助产科医师为患者拟定个性化的诊疗措施以改善妊娠结局。
